FASTENING PART AND METHOD FOR FORMING FASTENING PART
A fastening part 1 has a pin body 3 that is inserted in a through hole formed in a member of an object to be installed. The pin body 3 has elastic sections 12A, 12B and locking parts 14A, 14B that form pairs. The elastic sections 12A, 12B extend along the direction of insertion in the through hole of the object into which the elastic sections are to be inserted, and the distal ends that serve as the leading ends when inserted in said through hole form free ends and are capable of elastic deformation. The locking parts 14A, 14B protrude in mutually opposite directions from the free ends of the respective elastic sections 12A, 12B in directions that intersect with the direction of flexural displacement of the free ends of said elastic sections 12A, 12B that results from elastic deformation of the elastic sections 12A, 12B.
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The present invention relates to a part that makes fastening between constituent members constituting a device, for example.
BACKGROUND ARTFor example, in order to cool a heat generation part such as a semiconductor element installed in a circuit board, a heat sink is sometimes attached to the circuit board. Various structures have been proposed as a structure of attaching a heat sink to a circuit board. PTL 1 discloses one of the proposals. In PTL 1, a heat sink is attached to a circuit board by using the following fastening part (a push pin). Specifically,
In an example of
The fastening part 104 includes a shaft body 110 that can be inserted through the through holes 106 and 107. A one-end side of the shaft body 110 is a distal end portion 111 which serves as a leading end when the shaft body 110 is inserted into the through holes 106 and 107, and has a tapered shape becoming thinner toward a distal end in order to be easily inserted into the through holes 106 and 107. A collar portion 112 is formed on the other end side of the shaft body 110.
Further, a locking portion 113 is formed in the shaft body 110, at a portion that protrudes from the circuit board 101 toward a lower side of
Closing the elastic pieces 114 enables the locking portion 113 to be inserted through the through holes 106 and 107. At the locking portion 113 that has passed through the through holes 106 and 107, the elastic pieces 114 are opened, and thereby, the extending distal ends of the elastic pieces 114 are locked on an opening edge of the through hole 107 in the circuit board 101. Accordingly, the fastening part 104 is prevented from falling out of the through holes 106 and 107 (prevented from slipping off).
The shaft body 110 is fitted, on a side of the collar portion 112 thereof, into a coil-shaped spring 115. The spring 115 is arranged in a compressed state between the collar portion 112 and an opening edge portion of the through hole 106 of the heat sink 100, and gives biasing force to the collar portion 112 and the heat sink 100. The biasing force of this spring 115, and pressing force based on the biasing force and directed from the locking portion 113 to the circuit board 101 fix the fastening part 104 to the circuit board 101 and the heat sink 100.
CITATION LIST Patent Literature[PTL 1] Japanese Laid-open Patent Publication No. 2014-183258
SUMMARY OF INVENTION Technical ProblemIn the fastening part 104 illustrated in
Further, when the shaft body 110 of the fastening part 104 is inserted through the through holes 106 and 107, the shaft body 110 needs to be pushed into the through holes 106 and 107 by large pushing force elastically deforming a plurality of the elastic pieces 114. There is a possibility that an impact caused by the pushing force is applied to the heat sink 100 and the circuit board 101 to thereby adversely influence the heat sink 100 and the circuit board 101.
In order to solve the above-described problem, the present invention has been conceived. In other words, a main object of the present invention is to provide a technique of a fastening part that can be easily attached to an attaching-target member, and can further achieve improvement in reliability of slip-off prevention and downsize the part.
Solution to ProblemA fastening part of the present invention includes a pin body that is inserted through a through hole formed in an attaching-target member.
The pin body includes:
elastically-deformable elastic sections that make a pair, each of the elastic sections extending along a direction of being inserted into the through hole and having a free end which is on side of distal end serving as leading end when being inserted into the through hole; and
locking portions that project from each side of free end of the elastic section and protrude in directions opposite to each other, projection directions of the locking portions being directions crossing to directions in which free ends of the elastic sections move due to elastic deformation of the elastic sections.
The elastic sections elastically deform in such a way that the locking portions are displaced in the directions opposite to the projection directions, thereby the pin body is enabled to be inserted into the through hole, and the locking portions are locked on an opening edge of the through hole through which the pin body is inserted, thereby the pin body is prevented from slipping out of the through hole.
A method for forming a fastening part of the present invention, includes:
forming, in a pin body that is inserted through a through hole formed in an attaching-target member, elastically-deformable elastic sections that make a pair, each of the elastic sections extending along a direction of being inserted into the through hole and having a free end which is on side of distal end serving as leading end when being inserted into the through hole; and
further forming, in the pin body, locking portions that project from each side of free end of the elastic section and protrude in directions opposite to each other, projection directions of the locking portions being directions crossing to directions in which free ends of the elastic sections move due to elastic deformation of the elastic sections.
Advantageous Effects of InventionAccording to the present invention, it is possible to provide a fastening part that can be easily attached to an attaching-target member, and can further achieve improvement in reliability of slip-off prevention and downsize the part.
The following describes example embodiments according to the present invention, with reference to the drawings.
First Example EmbodimentThe pin body 3 is a section that is inserted through a through hole 10 formed in an attaching-target member 9, as illustrated in
Provided on the free-end sides (distal-end sides) in the respective elastic sections 12A and 12B are locking portions 14A and 14B that protrude outward from the elastic sections 12A and 12B. Here, as illustrated in
The elastic sections 12A and 12B are designed to elastically deform in such a way to narrow the gap 13 and cancel displacing amount between the locking portions 14A and 14B in the directions β in order that the locking portions 14A and 14B can be put in an aligned state as illustrated in a plan view of
Sizes and shapes of the locking portions 14A and 14B are designed by taking into account a size and a shape of the through hole 10, in such a way that the locking portions 14A and 14B can be locked on the opening edge of the through hole 10 as described above and be inserted through the through hole 10.
Distal end faces of the elastic sections 12A and 12B are formed into tapered faces provided with inclined portions. In the first example embodiment, the tapered faces are formed into curved faces of conic-surface shapes. As illustrated in
In the first example embodiment, the tapered faces are inclined portions that guide elastic deformation of the elastic sections 12A and 12B when the pin body 3 is inserted into the through hole 10. In other words, the tapered faces are provided with the inclined portions that can receive pressing force of the P directions illustrated in
The pin body 3 in a state where a coil-shaped spring 20 as an elastic member is attached thereto is inserted, from the distal end portion 11, through the through hole 18 of the heat sink 16 and the through hole 10 of the circuit board 9 in order. At this time, because of sliding between the tapered faces at the distal end of the pin body 3 and the opening edges of the through holes 10 and 18, a pressing force P as illustrated in
In the first example embodiment, the collar portion 4 projects outward from the pin body 3 in directions along the opening edge of the through hole 18 of the heat sink 16, and is configured to have a size capable of locking the spring 20 attached to the pin body 3. In a state where the locking portions 14A and 14B of the pin body 3 are locked on the opening edge of the through hole 10, the spring 20 is arranged, in a compressed state, between the collar portion 4 and the opening edge of the through hole 18 of the heat sink 16. Thereby, the biasing force due to the spring 20 acts on the collar portion 4 and the opening edge of the through hole 18. Although this biasing force is force moving the pin body 3 in a direction (i.e., a direction of pulling the pin body 3 from the through holes 10 and 18) opposite to an insertion direction S, the locking portions 14A and 14B are pressed against and locked on the opening edge of the through hole 10, and then the pin body 3 is prevented from slipping off. The fastening part 1 is firmly attached to the circuit board 9 and the heat sink 16 by the force with which the locking portions 14A and 14B press the opening edge of the through hole 10, and the biasing force due to the spring 20.
The fastening part 1 according to the first example embodiment is configured as described above, and can obtain the advantageous effects described as follows. In other words, the locking portions 14A and 14B in the fastening part 1 protrude in the directions opposite to each other and project in the directions β that cross to the displacing directions α of the free ends of the elastic sections 12A and 12B. For this reason, for example, even when the elastic sections 12A and 12B elastically deform in the displacing direction α by an impact applied to the circuit board 9 due to falling or the like, the locking portions 14A and 14B can prevent a situation where a state of being locked on the opening edge of the through hole 10 of the circuit board 9 is dissolved. Thereby, a situation where the fastening part 1 falls off from the circuit board 9 can be prevented.
In the first example embodiment, the locking portions 14A and 14B are arranged to be displaced from each other in the directions β. For this reason, by an amount depending on this displaced amount, projecting amounts of the locking portions 14A and 14B can be increased. This is also an effective factor contributing to prevention of a situation where a state of locking the locking portions 14A and 14B on the opening edge of the through hole 10 of the circuit board 9 is dissolved.
The fastening part 1 according to the first example embodiment achieves, with a simple configuration, a configuration that can prevent a situation where the locked state of the locking portions 14A and 14B is dissolved, as described above.
Since a situation where the locked state of the locking portions 14A and 14B is dissolved can be prevented, the fastening part 1 even in the case of being formed of a resin material can achieve reliability of attachment at a level equivalent to that in the case of being formed of a metal. Thereby, forming the fastening part 1 of a resin material enables manufacture of the fastening part 1 at low cost without degradation in reliability.
In the first example embodiment, tapered faces are formed at the distal end portion 11 of the pin body 3. The tapered faces include the inclined portions that can receive pressing force (i.e., force elastically deforming the elastic sections 12A and 12B in such a way that the locking portions 14A and 14B are put in the aligned state) of the P direction while sliding on the opening edges of the through holes 10 and 18 by being inserted into the through holes 10 and 18. For this reason, although the locking portions 14A and 14B are formed at the distal end portion 11 of the pin body 3, the fastening part 1 can be easily attached by pushing the pin body 3 into the through holes 10 and 18 without using special tool or fittings, because of the tapered faces of the distal end portion 11.
Therefore, the fastening part 1 according to the first example embodiment can be easily attached to an attaching-target member, and can further achieve improvement in reliability of slip-off prevention and downsize the part.
Second Example EmbodimentThe following describes a second example embodiment according to the present invention.
The fastening part 30 according to this second example embodiment includes a pin body 31 that is inserted through a through hole formed in an attaching-target member. Similarly to the first example embodiment, formed in the pin body 31 is a gap 33 extending in a direction along a direction of insertion into the through hole, from a distal end portion 32 serving as a leading end at the time of being inserted into the through hole, and the gap 33 forms elastic sections 34A and 34B making a pair. The elastic sections 34A and 34B form free ends on distal end sides, and elastically deform. In the second example embodiment, the free ends of the elastic sections 34A and 34B are configured to be easily elastically displaced in the directions α illustrated in
On the free end sides of the elastic sections 34A and 34B, locking portions 35A and 35B are formed to protrude. In other words, the locking portions 35A and 35B are configured to project, from the free-end sides of the elastic sections 34A and 34B, in the directions opposite to each other along the directions β crossing the displacing directions α of the free ends. The locking portions 35A and 35B are locked on the opening edge of the through hole through which the pin body 31 has been inserted, to thereby prevent the pin body 31 from slipping out of the through hole. Further, the locking portions 35A and 35B have shapes and sizes enabling insertion into the through hole by elastic deformation of the elastic sections 34A and 34B in the directions of dissolving the locked state of the locking portions 35A and 35B.
In the second example embodiment, the locking portions 35A and 35B project in the directions β crossing the displacing directions α of the free ends of the elastic sections 34A and 34B. For this reason, similarly to the first example embodiment, even when the elastic sections 34A and 34B bend and deform due to external force caused by falling or the like, a situation where the locked state of the locking portions 35A and 35B is dissolved can be prevented since the displacing direction is a direction different from the projecting directions of the locking portions 35A and 35B. Thereby, the fastening part 30 can improve reliability of the attachment. Further, because of the simple configuration, the fastening part 30 can easily achieve miniaturization, and can be easily attached to an attaching-target member.
Other Example EmbodimentsThis invention is not limited to the first and second example embodiments, and can be variously configured to be embodied. For example, in the first example embodiment, shapes of the locking portions 14A and 14B are circular (fan-shapes), and in the second example embodiment, shapes of the locking portions 35A and 35B are quadrilateral. In contrast to this, the locking portions may be configured at least to project in the directions crossing the displacing directions of the free ends of the elastic sections and be capable of being locked on the opening edge of the through hole, and there is not a limitation on shapes of the locking portions.
In the first example embodiment and the second example embodiment, the projecting directions β of the locking portions 14A, 14B, 35A, and 35B are directions perpendicular to the displacing directions α of the free ends of the elastic sections. In contrast to this, projecting directions of the locking portions may cross the displacing directions α, and are not limited to the perpendicular directions. For example, although an opening shape of the through hole is often circular because of a manufacturing manner, there is also supposed a case where an opening shape of the through hole has a shape other than a circular shape. In such a case, by taking the opening shape of the through hole into account, the locking portions are designed in such a way that the projecting directions of the locking portions are appropriate directions crossing the displacing directions of the free ends of the elastic sections.
Further, in the first example embodiment, the distal end faces of the elastic sections 12A and 12B are formed into tapered faces. In contrast to this, for example, depending on a size of the fastening part, there is a case where the elastic sections can be elastically deformed easily, and in such a case, the distal end faces of the elastic sections do not need to be tapered faces.
Furthermore, a material forming the fastening part according to the present invention may be a resin material or a metal depending on requested price, strength, and the like, for example.
The present invention is described above by citing the above-described example embodiments as model examples. However, the present invention is not limited to the above-described example embodiments. In other words, various configurations that can be understood by those skilled in the art can be applied to the present invention within the scope of the present invention.
The present application claims priority based on Japanese patent application No. 2015-109942 filed on May 29, 2015, the entire disclosure of which is incorporated herein.
REFERENCE SIGNS LIST
- 1, 30 Fastening part
- 3, 31 Pin body
- 4 Collar portion
- 12A, 12B, 34A, 34B Elastic section
- 14A, 14B, 35A, 35B Locking portion
- 10, 18 Through hole
Claims
1. A fastening part comprising
- a pin body that is inserted through a through hole formed in an attaching-target member,
- the pin body including:
- elastically-deformable elastic sections that make a pair, each of the elastic sections extending along a direction of being inserted into the through hole and having a free end which is on side of distal end serving as leading end when being inserted into the through hole; and
- locking portions that project from each side of free end of the elastic section and protrude in directions opposite to each other, projection directions of the locking portions being directions crossing to directions in which free ends of the elastic sections move due to elastic deformation of the elastic sections, wherein
- the elastic sections elastically deform in such a way that the locking portions are displaced in the directions opposite to the projection directions, thereby the pin body is enabled to be inserted into the through hole, and the locking portions are locked on an opening edge of the through hole through which the pin body is inserted, thereby the pin body is prevented from slipping out of the through hole.
2. The fastening part according to claim 1, wherein each of the locking portions projects also in the direction in which the free end of the elastic section moves, and the elastic sections elastically deform in such a way that the locking portions are displaced in directions opposite to the projection directions, thereby the locking portions are enabled to be inserted into the through hole.
3. The fastening part according to claim 1, wherein distal end faces of the free ends of the elastic sections are formed into tapered faces inclined with respect to an insertion direction into the through hole, and the tapered faces include inclined portions that receive pressing force while sliding on the opening edge of the through hole when being inserted into the through hole, thereby guiding elastic deformation of the elastic sections in such a way that the elastic sections elastically deform and the locking portions are displaced to allow insertion into the through hole.
4. The fastening part according to claim 3, wherein the tapered faces are curved faces of conic-surface shape, and a conic-vertex position on the tapered faces is displaced from a center axis of the pin body.
5. A method for forming a fastening part, comprising:
- forming, in a pin body that is inserted through a through hole formed in an attaching-target member, elastically-deformable elastic sections that make a pair, each of the elastic sections extending along a direction of being inserted into the through hole and having a free end which is on side of distal end serving as leading end when being inserted into the through hole; and
- further forming, in the pin body, locking portions that project from each side of free end of the elastic section and protrude in directions opposite to each other, projection directions of the locking portions being directions crossing to directions in which free ends of the elastic sections move due to elastic deformation of the elastic sections.
Type: Application
Filed: May 23, 2016
Publication Date: Jun 7, 2018
Applicant: NEC Corporation (Minato-ku, Tokyo)
Inventor: Kenji OKUMURA (Tokyo)
Application Number: 15/576,933